Modeling, Fabrication, and Testing of a 3D-Printed Coriolis Mass Flow Sensor

Abstract

This paper presents the modeling, fabrication, and testing of a 3D-printed Coriolis mass flow sensor. The sensor contains a free-standing tube with a circular cross-section printed using the LCD 3D-printing technique. The tube has a total length of 42 mm, an inner diameter of about 900 µm, and a wall thickness of approximately 230 µm. The outer surface of the tube is metalized using a Cu plating process, resulting in a low electrical resistance of 0.5 Ω. The tube is brought into vibration using an AC current in combination with a magnetic field from a permanent magnet. The displacement of the tube is detected using a laser Doppler vibrometer (LDV) that is part of a Polytec MSA-600 microsystem analyzer. The Coriolis mass flow sensor has been tested over a flow range of 0–150 g/h for water, 0–38 g/h for isopropyl alcohol (IPA), and 0–50 g/h for nitrogen. The maximum flow rates of water and IPA resulted in less than a 30 mbar pressure drop. The pressure drop at the maximum flow rate of nitrogen is 250 mbar.

Compact Micro-Coriolis Mass-Flow Meter with Optical Readout

“…Based on the analytical model of a U-shaped Coriolis mass-flow sensor presented in [ 24 ], the mass-flow sensitivity can be expressed as: where is the amplitude of the displacement in direction of the tube segment with length due to the Coriolis forces, is the amplitude of the angular displacement in the actuation mode, is the mass-flow rate, and is the total mass of the tube and the fluid inside the tube. and are the length of the tube in and direction as indicated in Figure 2 , and are the resonance frequencies of the tube in actuation (twist) and detection (swing) mode, respectively, and is the quality factor for the detection mode.…”

“…As will be shown below, the phase difference between the motion in points (1) and ( 2) is a measure of the mass flow. Based on the analytical model of a U-shaped Coriolis mass-flow sensor presented in [24], the mass-flow sensitivity can be expressed as:…”

“…To prevent channel deformations due to pressure, particularly when the tube wall is relatively thin, it is necessary to have a circular cross-section for the channel [ 16 ]. In this regard, some devices were developed based on glass microcapillaries [ 19 , 20 , 21 , 22 , 23 ], 3D printing [ 24 ], and nickel electroplating [ 16 ]. The proposed glass microcapillaries are made by thermally elongating glass tubes.…”

“…In [ 21 ], a diameter-to-wall-thickness ratio of 8.5 was achieved. Three-dimensionally printed channels were reported in [ 24 ] with a ratio up to 3.9. In this case, the maximum ratio was limited by the smallest wall thickness of the tube that can be reliably printed without resulting in leakage.…”

“… The ratio of the tube inner diameter to wall thickness versus the equivalent inner diameter of the cross-section for different fabrication methods. The marker used for each fabrication method corresponds to the resulting cross-sectional shape of the tube [ 2 , 5 , 8 , 10 , 11 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 21 , 24 , 25 ]. …”